Conductive paste and laminated ceramic electronic component

ABSTRACT

A laminated ceramic electronic component, for example, monolithic ceramic capacitor, in which the delamination does not occur during baking and having superior thermal shock and moisture load resistance characteristics is provided. A conductive paste, used with advantage to form an internal electrode of the laminated ceramic electronic component, and a laminated ceramic electronic component using the conductive paste is provided. The conductive paste is composed of a conductive powder which is primarily Ni, an organic vehicle, a compound A containing at least one of Mg and Ca and which is an organic acid metal salt, oxide powder, metal organic complex salt and/or an alkoxide, and a compound B, having a hydrolyzable reactive group containing at least one of Ti and Zr, which adheres to the surface of the conductive powder.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a conductive paste and alaminated ceramic electronic component. In particular, the presentinvention relates to a conductive paste used with advantage as aninternal electrode of a laminated ceramic electronic component, andrelates to a monolithic ceramic capacitor.

[0003] 2. Description of the Related Art

[0004] Hitherto, laminated ceramic electronic components, such asmonolithic ceramic capacitors, have been provided with a laminateincluding a plurality of laminated ceramic layers and at least oneinternal electrode formed along a specified interface between theaforementioned ceramic layers.

[0005] In such a laminated ceramic electronic component, in general, theinternal electrode is formed by printing and baking a conductive pastein which a conductive powder and an organic vehicle are dispersed in asolvent. More specifically, when the laminated ceramic electroniccomponent is manufactured, a specified ceramic green sheet, whichbecomes a ceramic layer by baking, is printed with the conductive paste,which becomes an internal electrode, so as to form an electrode coating.Thereafter, a plurality of the aforementioned green sheets arelaminated, are press-adhered, and are baked, so that the sintering ofthe internal electrodes is completed concurrently with the completion ofsintering of the ceramic layers, and a ceramic laminate provided withthe internal electrodes is formed. At this time, the melting point ofthe conductive powder constituting the internal electrodes must behigher than the sintering temperature of the ceramic. When the meltingpoint of the conductive powder is lower than the sintering temperatureof the ceramic, the conductive powder is molten during the baking, sothat a break or crack is generated in the internal electrode after thebaking so as to reduce coverage. Therefore, as the conductive powderconstituting the internal electrode, Pt, Pd, W, Nb, Ni, etc., can beselected, and in addition to this, in order to realize reduction of thecost, a base metal, e.g., Ni, is used as the conductive powder.

[0006] In the laminated ceramic electronic component using such a basemetal such as Ni for the internal electrode, however, accompanying thedecrease in the layer thickness and the increase in the number of layersof the ceramic layers, a large residual stress is generated at theinterface between the internal electrode and the ceramic layer due tothe difference of shrinkages and the difference of coefficients ofthermal expansion between the electrode coating formed by printing andthe green ceramic layer during the baking. As a consequence, there is aproblem in that the thermal shock resistance of the laminated ceramicelectronic component is degraded. Furthermore, there is a problem inthat the reliability at a high temperature and high humidity, that is,the moisture load resistance characteristics, is also degradedaccompanying the decrease in the layer thickness and the increase in thenumber of layers of the ceramic layers.

[0007] Accompanying the decrease in the thickness of each ceramic layer,the thickness of the internal electrode must be decreased. Accordingly,the particle diameter of the conductive powder in the conductive pastefor constituting the internal electrode must be further decreased. Whenthe particle diameter of the conductive powder is further decreased,since the shrinkage of the internal electrode due to the sintering ofthe conductive powder occurs at a lower temperature during the baking,there is a problem in that delamination is likely to occur.

[0008] In order to solve the latter problem, for example, in JapaneseExamined Patent Application Publication No. 7-56850, a monolithicceramic capacitor in which a Ni internal electrode and a ceramic layerare connected with an aluminosilicate layer is disclosed. Regarding thismonolithic ceramic capacitor, however, an improvement of theaforementioned problem, that is, the improvement of the thermal shockresistance, is not intended.

[0009] Furthermore, in Japanese Unexamined Patent ApplicationPublication No. 8-259847, a conductive paste using a metallic powdercoated with a reaction product of an organic silicon compound and wateris disclosed. When this conductive paste is used for an internalelectrode of a monolithic ceramic capacitor, however, since abnormalparticle growth of the ceramic occurs due to a reaction of silicon inthe paste and the ceramic, this is not effective to improve theaforementioned problem, that is, to improve the thermal shockresistance.

SUMMARY OF THE INVENTION

[0010] Accordingly, it is an object of the present invention to providea conductive paste in which the delamination does not occur during astep of baking, having superior thermal shock resistance and superiormoisture load resistance characteristics. It is another object toprovide a laminated ceramic electronic component in which an internalelectrode is formed using the aforementioned conductive paste.

[0011] In order to achieve the aforementioned objects, a conductivepaste according to an aspect of the present invention is composed of aconductive powder primarily containing Ni, an organic vehicle, and acompound A containing at least one of Mg and Ca and at least onematerial selected from the group consisting of an organic acid metalsalt, an oxide powder, a metal organic complex salt and an alkoxide, inwhich a compound B having a hydrolyzable reactive group containing atleast one of Ti and Zr adheres to the surface of the aforementionedconductive powder.

[0012] A conductive paste according to another aspect of the presentinvention is composed of a conductive powder primarily containing Ni andan organic vehicle in which a compound A and a compound B adhere to thesurface of the aforementioned conductive powder, the compound A containsat least one of Mg and Ca and is at least one organic acid metal salt,oxide powder, metal organic complex salt and/or alkoxide, and thecompound B has a reactive group containing at least one of Ti and Zr.

[0013] The reactive group of the aforementioned compound B is preferablyan alkoxyl group.

[0014] The aforementioned compound B is preferably an alkoxide.

[0015] The aforementioned compound B is preferably a coupling agent.

[0016] The adhesion amount of the aforementioned compound B ispreferably about 0.1% to 5.0% by weight in terms of TiO₂ and ZrO₂relative to 100% by weight of the aforementioned conductive powder.

[0017] The mole ratio of the total amount of Ti and Zr, in terms of TiO₂and ZrO₂ contained in the aforementioned compound B, relative to thetotal amount of Mg and Ca, in terms of MgO and CaO contained in theaforementioned compound A, is preferably about 0.5 to 4.0.

[0018] A laminated ceramic electronic component according to anotheraspect of the present invention is provided with a ceramic laminateincluding a plurality of laminated ceramic layers and an internalelectrode formed along an interface between the aforementioned ceramiclayers in which the aforementioned internal electrode is formed bybaking the aforementioned conductive paste according to the presentinvention.

[0019] The laminated ceramic electronic component according to thepresent invention is preferably further provided with a plurality ofterminal electrodes provided at different positions on the end faces ofthe aforementioned laminate, and in which a plurality of aforementionedinternal electrodes are electrically connected to one of the terminalelectrodes.

[0020] The aforementioned ceramic layer in the laminated ceramicelectronic component according to the present invention may be composedof a dielectric ceramic primarily containing barium titanate.

BRIEF DESCRIPTION OF THE DRAWING

[0021]FIG. 1 is a sectional view of a monolithic ceramic capacitoraccording to an embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The conductive paste according to the present invention containsa compound A and a compound B, and at least the compound B must adhereto the surface of the conductive powder by hydrolysis. An embodiment ofa treatment method for adhering the compound B to the surface of theconductive powder is explained below. The conductive paste and themonolithic ceramic capacitor according to the present invention are notlimited to be produced by the following one embodiment.

[0023] First, as a conductive powder, for example, a Ni powder isprepared. As the conductive powder, materials primarily containing Ni,for example, materials containing Cu, Ag, Au, Pt, Pd, alloys thereof,etc., in addition to Ni can be appropriately selected and can be used.The average particle diameter of the conductive powder is notspecifically limited. In general, when the conductive powder is a fineparticle, since the shrinkage of the internal electrode due to thesintering of the conductive powder occurs at a lower temperature,delamination is likely to occur. According to the present invention,however, this can be prevented from occurring, and the present inventionexhibit remarkable effects, when the average particle diameter of theconductive powder is about 10 nm to 200 nm.

[0024] Next, the conductive powder is dispersed in such an organicsolvent such as an alcohol so as to produce a suspension. In the case inwhich a conductive powder having an average particle diameter of 1 μm orless is used, in order to accelerate dispersion, an agitation iseffective, and a dispersion machine, for example, an ultrasonichomogenizer, may be used, if necessary.

[0025] The compound B is added to the aforementioned suspension and isdispersed. The compound B must have a hydrolyzable reactive groupcontaining at least one of Ti and Zr. Specifically, the compound Bpreferably contains one or more alkoxides or acetylacetonates, and morespecifically, for example, tetrapropoxytitanium, titaniumoxyacetylacetonato, tetrabutoxyzirconium, tetrapropoxyzirconium andzirconium acetylacetonato, can be mentioned.

[0026] Subsequently, water is dropped into the resulting suspension soas to hydrolyze the compound B. In the case in which the compound B israpidly hydrolyzed, if necessary, a mixed solution in which water isdiluted with an organic solvent, or a mixed solution in which achelating agent, for example, amines and carboxylic acids, isappropriately added, is preferably used for the dropping. In the case inwhich the compound B is slowly hydrolyzed, it is preferable to use amixed solution in which a hydrolysis catalyst, for example, mineralacids and ammonia water, has been appropriately added into water.

[0027] When compound A is adhered to the conductive powder in additionto the compound B, the compound A is also added into the suspension andis dispersed when the aforementioned compound B is added into thesuspension and is dispersed.

[0028] The compound A must contain at least one of Mg and Ca and be atleast one material selected from the group consisting of an organic acidmetal salt, an oxide powder, a metal organic complex salt and analkoxide. As the compound A, specifically, organic acid metal salts, forexample, magnesium formate, magnesium acetate, magnesium lactate,magnesium stearate, magnesium octylate, calcium formate, calciumacetate, calcium lactate, calcium stearate, and calcium octylate, metalorganic complex salts, for example, magnesium acetylacetonato andcalcium acetylacetonato, and alkoxides, for example,di-n-butoxymagnesium and diethoxymagnesium, can be mentioned.

[0029] In the case in which the compound A is also adhered to theconductive powder, the adhesion form is not specifically limited. Forexample, when the compound A has a reactive group such as an alkoxide,the compound A is hydrolyzed so as to adhere to the conductive powder.

[0030] Then, the solvent and water are removed from the suspension byfiltration, decantation, etc., and drying was performed so as to producea conductive paste to which the hydrolysis product of the compound B isadhered or the compound A is further adhered.

[0031] The adhesion amount of the compound B according to the presentinvention is preferably about 0.1% to 5.0% by weight in terms of TiO₂and ZrO₂ relative to 100% by weight of the conductive powder. When theaforementioned adhesion amount is about 0.1% by weight or more, aneffect of decreasing a residual stress generated at an interface betweenthe internal electrode and the ceramic layer is likely to be exhibited,so that the delamination is reliably prevented from generating. On theother hand, when the aforementioned adhesion amount is about 5.0% byweight or less, an effect of improving the thermal shock resistance ofthe electrode formed with printing and baking the aforementionedconductive paste is likely to be exhibited.

[0032] The mole ratio of the total amount of Ti and Zr, in terms of TiO₂and ZrO₂ contained in the compound B according to the present invention,relative to the total amount of Mg and Ca, in terms of MgO and CaOcontained in the compound A according to the present invention, ispreferably about 0.5 to 4.0. When the aforementioned mole ratio is about0.5 or more, the effect of decreasing residual stress generated at aninterface between the internal electrode and the ceramic layer is likelyto be exhibited, and the delamination is reliably prevented fromgenerating. On the other hand, when the aforementioned mole ratio isabout 4.0 or less, the effect of improving the thermal shock resistanceof the electrode formed with printing and baking the aforementionedconductive paste is likely to be exhibited.

[0033] In an embodiment of the conductive paste according to the presentinvention, the conductive paste is composed of the conductive powder inwhich the compound B is adhered to the surface thereof by, for example,the aforementioned method, the organic vehicle, and compound A. Inanother embodiment of the conductive paste according to the presentinvention, the conductive paste is composed of the conductive powder inwhich compound A and compound B are adhered to the surface thereof by,for example, the aforementioned method, and the organic vehicle.

[0034] The method for manufacturing the conductive paste according tothe present invention is not specifically limited. For example, theconductive powder is dispersed in an organic vehicle and is kneaded soas to produce the conductive paste in a manner similar to that inconventional conductive pastes.

[0035] In the manufacture of the conductive paste according to thepresent invention, the conductive powder subjected to the adhesiontreatment of the compound A and the compound B may be used as it is,although may be used after being subjected to further heat treatment inair or nitrogen at 200° C. to 800° C., if necessary.

[0036] An embodiment of the laminated ceramic electronic componentaccording to the present invention is explained below in detail withreference to FIG. 1. That is, a laminated ceramic electronic component 1is provided with a ceramic laminate 2, internal electrodes 3, terminalelectrodes 4, and plating films 5.

[0037] The ceramic laminate 2 is formed with baking a green ceramiclaminate in which a plurality of ceramic layers 2 a made of a dielectricmaterial primarily containing, for example, BaTiO₃.

[0038] The internal electrodes 3 are provided between the ceramic layers2 a in the ceramic laminate 2, and are formed of the conductive pasteaccording to the present invention baked concurrently with the greenceramic layers 2 a by baking a plurality of green ceramic layers 2 aprinted with the conductive paste. Each of the end edges of the internalelectrodes 3 and 3 is formed, for example, to expose at one of end facesof the ceramic laminate 2.

[0039] For example, in the case in which one end of each of the internalelectrodes 3 is exposed at the end face of the ceramic laminate 2, theterminal electrodes 4 are formed by coating the conductive paste forconstituting the terminal electrodes on the end face of the ceramiclaminate 2, and by baking these, so that the terminal electrodes 4 areelectrically and mechanically connect to the internal electrodes 3.

[0040] The plating films 5 are made of, for example, an electrolessplating of Sn, Ni, etc., and a solder plating, and at least one layer isformed on the terminal electrodes 4.

[0041] The material for the ceramic laminate 2 is not limited to theaforementioned embodiment, and may be, for example, a dielectricmaterial, for example, PbZrO₃, an insulating material, a magneticmaterial and a semiconducting material.

[0042] The number of layers of the internal electrodes 3 of thelaminated ceramic electronic component according to the presentinvention is not limited to the aforementioned embodiment, and anarbitrary number of layers may be formed.

[0043] The terminal electrodes 4 are usually formed by coating theconductive paste containing a conductive powder, which is a material forthe terminal electrode, on the baked ceramic laminate 2, and by bakingthe conductive paste, although, the terminal electrodes may be formed bycoating the conductive paste on a green ceramic laminate before bakingand by baking the conductive paste concurrently with the green ceramiclaminate. The method for forming the terminal electrodes and the numberthereof are not limited to the aforementioned embodiment.

[0044] The plating films 5 are not limited to the aforementionedembodiment, and the plating film may not be provided. Furthermore, anarbitrary number of layers may be formed.

EXAMPLES Example 1

[0045] In the present embodiment, a monolithic capacitor having astructure as shown in FIG. 1 was manufactured as a laminated ceramicelectronic component.

[0046] In order to produce a ceramic represented by the formula

{(Ba_(1-x)Ca_(x))O}_(m)(Ti_(1-y)Zr_(y))O₂,

[0047] wherein 1.005≦m≦1.03, 0.02≦x≦0.22, and 0<y≦1.20, as anon-reducing dielectric ceramic constituting the ceramic layers,material powders having an average diameter of 0.3 μm for the ceramicwere weighed, mixed, and calcined to prepare a calcined mixture. Apolyvinyl butyral-based binder and an organic solvent, for example,ethanol, were added thereto, and those were wet-mixed with a ball millso as to prepare ceramic slurry. Thereafter, the resulting ceramicslurry was shaped into sheets by a doctor blade method so as to producerectangular ceramic green sheets of 5 μm in thickness.

[0048] 100 g of Ni powder produced using a chemical vapor depositionmethod was dispersed into 0.2 liters of ethanol so as to produce asuspension. The resulting suspension was subjected to a dispersiontreatment with an ultrasonic homogenizer.

[0049] A predetermined amount of magnesium acetate as the compound A anda predetermined amount of tetrapropoxytitanium as the compound B wereprepared. Those were dissolved into the aforementioned suspension andwere agitated so as to produce mixed suspensions for Samples 1 to 15.

[0050] Next, a mixed solution of 10 g of pure water and 10 g of ammoniawater was dropped into each of the mixed suspensions for Samples 1 to 15using a roller pump. Subsequently, each of the resulting mixture wasagitated for 12 hours so that magnesium acetate as the compound A wasadhered to the surface of the Ni powder, and tetrapropoxytitanium as thecompound B was hydrolyzed and was adhered to the surface of the Nipowder. Then, solid-liquid separation was performed by decantation, andthe resulting precipitate was dried at 120° C. for 12 hours so as toproduce each of conductive powders of Samples 1 to 15, to which ahydrolysis product of tetrapropoxytitanium and magnesium acetate wereadhered. The contents of the hydrolysis product of tetrapropoxytitaniumand the magnesium acetate in terms of TiO₂ and MgO, respectively, areshown in Table 1.

[0051] Conductive powders of Samples 16 to 18 in which magnesium acetateas the compound A was only adhered to the surface of the Ni powder wereproduced in a manner similar to that in the aforementioned Samples 1 to15, except that tetrapropoxytitanium as the compound B was not addedinto the suspension.

[0052] 42% by weight of each of conductive powders of Samples 1 to 18,44% by weight of an organic vehicle produced by dissolving 6 parts byweight of ethyl cellulose-based organic binder into 94 parts by weightof terpineol, and 14% by weight of terpineol were dispersed and weremixed by a ball mill method so as to produce conductive pastes ofSamples 1 to 18.

[0053] Regarding each of the samples, the contents in terms of oxidesrelative to 100% by weight of the conductive powder, and a mole ratioTiO₂/MgO are summarized in Table 1.

[0054] The aforementioned ceramic green sheets were screen printed witheach of the conductive pastes of Samples 1 to 18 so as to produceconductive paste films for constituting the internal electrodes. At thistime, the thickness of electrode coating, that is, the thickness interms of Ni metal determined by an X-ray coating thickness gauge, wasadjusted to 0.5 μm by changing the thickness of the screen pattern.

[0055] Subsequently, a ceramic laminate was produced in which aplurality of aforementioned ceramic green sheets were laminated so thatthe sides exposing the conductive paste film thereof appeared onalternate sheets. The resulting ceramic laminate was heated to atemperature of 300° C. in an atmosphere of nitrogen so as to burn theorganic binder, and thereafter, was baked in a non-reducing atmosphereof H₂—N₂—H₂ O gas so as to produce ceramic laminates of Samples 1 to 18.Regarding the step of baking, the temperature was raised at a rate of200° C./hr, and was kept at 1,200° C. for 2 hours. The cooling rate was200° C./hr.

[0056] Both end faces of the ceramic laminates of Samples 1 to 18 werecoated with a conductive paste containing silver, and those were bakedin an atmosphere of N₂-Air at a temperature of 800° C., so that terminalelectrodes electrically connected to the internal electrodes wereformed. Thereafter, Ni plating layers were formed on the aforementionedterminal electrodes, and furthermore, solder plating layers were formedon the Ni plating layers so as to produce monolithic capacitors ofSamples 1 to 18. The external dimensions of the resulting monolithiccapacitor were 1.6 mm in width, 3.2 mm in length and 1.2 mm inthickness. The thickness of the internal electrode was 0.7 μm, thethickness of the dielectric ceramic layer interposed between theinternal electrodes was 3 μm, and the total number of the effectivedielectric ceramic layers was 150.

[0057] Regarding the monolithic capacitors of Samples 1 to 18,delamination occurrence rates, dielectric constants, and average failuretimes in accelerated life tests were measured. The results thereof andevaluation results are summarized in Table 1.

[0058] Regarding the delamination occurrence rate, 100 test pieces ofeach Sample were prepared and were cut in a plane orthogonal to thedirection of length. The cut surface was polished while being fixed witha resin, and the polished surface was observed with a microscope for thepresence or absence of cracks. The cracks were counted and theoccurrence rates relative to the total number of 100 were determined.

[0059] Regarding the average failure times in accelerated life tests,changes of insulation resistance of the test pieces with time weremeasured while 10 V/mm of direct current voltage was applied at 150° C.The time at which the insulation resistance reached 10⁵ Ω or less wasregarded as the time of failure occurrence, and an average time elapseduntil the failure occurred of the 100 test pieces was determined.

[0060] Regarding the evaluation, samples in which the delaminationoccurrence rate was 0%, the dielectric constant was higher than those ofSamples 17 and 18 as comparative examples, and the average failure timewas greater than those of Samples 17 and 18 as comparative examples wereindicated as “Excellent” as samples within an especially preferablerange of the present invention. Samples in which only the dielectricconstant was lower than those of monolithic capacitors of Samples 17 and18 as comparative examples were indicated as “Good” as samples within apreferable range of the present invention. Samples in which thedielectric constant or the average failure time was at a low levelcompared to that of the aforementioned samples indicated as “Excellent”or “Good”, but the effects were superior compared to those of themonolithic capacitors of Samples 17 and 18 were indicated as “Fair” assamples within the range of the present invention. Samples ofcomparative examples were indicated as “Poor”. TABLE 1 Conductive PowderMonolithic Capacitor Compound B Accelerated Compound A Tetrapropoxy LifeTest Magnesium acetate titanium Content Delamination Average FailureSample Content in terms of in terms of TiO₂ TiO₂/MgO OccurrenceDielectric Time No. MgO (wt %) (wt %) (mol %) Rate (n = 100) Constant(hr) Evaluation 1 0.3 0.1 0.2 0 2,070 78 Good 2 0.1 0.1 0.5 0 3,130 77Excellent 3 0.01 0.1 4.0 0 3,160 80 Excellent 4 0.008 0.1 6.0 0 2,780 30Good 5 3.0 1.0 0.2 0 2,100 81 Good 6 1.0 1.0 0.5 0 3,180 76 Excellent 70.1 1.0 4.0 0 3,230 75 Excellent 8 0.8 1.0 6.0 0 2,600 33 Good 9 13.05.0 0.2 0 2,080 80 Good 10 5.0 5.0 0.5 0 3,480 79 Excellent 11 0.6 5.04.0 0 3,340 72 Excellent 12 0.4 5.0 6.0 0 3,210 37 Good 13 18.0 7.0 0.20 1,680 26 Fair 14 7.0 7.0 0.5 0 2,690 22 Fair 15 0.9 7.0 4.0 0 3,120 24Fair 16 1.0 0.0 0.0 100 — — Poor 17 5.0 0.0 0.0 82 2,150  2 Poor 18 10.00.0 0.0 55 1,730  3 Poor

[0061] As is clear from Table 1, regarding the monolithic capacitors ofSamples 2, 3, 6, 7, 10 and 11, in which tetrapropoxytitanium as thecompound B was hydrolyzed and was adhered at a content of 0.1 to 5.0% byweight in terms of TiO₂ relative to 100% by weight of the conductivepowder, and the mole ratio of the amount of Ti in terms of TiO₂contained in tetrapropoxytitanium as the compound B, relative to theamount of Mg in terms of MgO contained in magnesium acetate as thecompound A, was within the range of 0.5 to 4.0, the delaminationoccurrence rates of all samples were 0%, the dielectric constants weresufficiently high as 3,130 to 3,480 compared to the dielectric constantof 2,150 of the monolithic capacitor of Sample 17 as the comparativeexample, and the average failure times in the accelerated life testswere very long as 75 to 80 hours compared to the average failure time of3 hours of the monolithic capacitor of Sample 18 as the comparativeexample, so that these samples were within the especially preferablerange of the present invention.

[0062] Regarding the monolithic capacitors of Samples 1, 5 and 9, inwhich tetrapropoxytitanium as the compound B was hydrolyzed and wasadhered at a content of 0.1 to 5.0% by weight in terms of TiO₂ relativeto 100% by weight of the conductive powder, and the mole ratio of theamount of Ti in terms of TiO₂ contained in tetrapropoxytitanium as thecompound B, relative to the amount of Mg in terms of MgO contained inmagnesium acetate as the compound A, was less than 0.5, the dielectricconstants were 2,070 to 2,100 and were slightly inferior to thedielectric constant of 2,150 of the monolithic capacitor of Sample 17 asthe comparative example, although these values were within theacceptable range as a dielectric constant of a monolithic capacitor.Furthermore, the delamination occurrence rates of all samples were 0%,and the average failure times in the accelerated life tests were verylong as 78 to 81 hours compared to the average failure time of 3 hoursof the monolithic capacitor of Sample 18 as the comparative example, sothat these samples were within the preferable range of the presentinvention.

[0063] Regarding the monolithic capacitors of Samples 4, 8 and 12, inwhich tetrapropoxytitanium as the compound B was hydrolyzed and wasadhered in the content of 0.1 to 5.0% by weight in terms of TiO₂relative to 100% by weight of the conductive powder, and the mole ratioof the amount of Ti in terms of TiO₂ contained in tetrapropoxytitaniumas the compound B, relative to the amount of Mg in terms of MgOcontained in magnesium acetate as the compound A, exceeded 4.0, theaverage failure times in the accelerated life tests were short as 30 to37 hours and were inferior to those of the aforementioned monolithiccapacitors of Samples 2, 3, 6, 7, 10 and 11 which were within theespecially preferable range of the present invention, but theaforementioned average failure times were very long compared to theaverage failure time of 3 hours of the monolithic capacitor of Sample 18as the comparative example. In addition, the delamination occurrencerates of all samples were 0%, and the dielectric constants weresufficiently high at 2,600 to 3,210 compared to the dielectric constantof 2,150 of the monolithic capacitor of Sample 17 as the comparativeexample, so that these samples were within the preferable range of thepresent invention.

[0064] Regarding the monolithic capacitors of Samples 13 to 15, in whichtetrapropoxytitanium as the compound B was hydrolyzed and was adhered inthe content of 7.0% by weight in terms of TiO₂ relative to 100% byweight of the conductive powder, the dielectric constant were 1,680 to3,120, the value of Sample 13 was inferior to the dielectric constant of2,150 of the monolithic capacitor of Sample 17 as the comparativeexample. The average failure times in the accelerated life tests wereshort as 22 to 26 hours and were inferior to those of the aforementionedmonolithic capacitors of Samples 2, 3, 6, 7, 10 and 11 which were withinthe especially preferable range of the present invention, but theaforementioned average failure times were within the acceptable range asa dielectric constant of a monolithic capacitor, and were sufficientlylong compared to the average failure time of 3 hours of the monolithiccapacitor of Sample 18 as the comparative example. In addition, thedelamination occurrence rates of all samples were 0%, so that thesesamples were within the range of the present invention.

[0065] On the other hand, regarding the monolithic capacitors of Samples16 to 18, in which the compound B was not hydrolyzed and was not adheredto the Ni powder, the delamination occurrence rates were high as 55% to100%, and the average failure times in the accelerated life tests couldnot be measured or were very low as 3 hours or less, so that thesesamples were inferior. Regarding the monolithic capacitor of Sample 16,since the delamination occurrence rates were 100%, the dielectricconstant and the average failure time could not be measured.

Example 2

[0066] The conductive powders of Samples 19 to 36 were prepared and themonolithic capacitors of Samples 19 to 36 were produced in a mannersimilar to that in Example 1, except that magnesium naphthenate was usedas the compound A, and tetrabutoxyzirconium was used as the compound B.The contents in terms of oxides relative to 100% by weight of theconductive powder and the mole ratio ZrO₂/MgO of each of samples were asshown in Table 2.

[0067] Regarding the monolithic capacitors of Samples 19 to 36,delamination occurrence rates, dielectric constants, and average failuretimes in accelerated life tests were measured. The results thereof andevaluation results are summarized in Table 2. The methods for each ofmeasurements and evaluations were similar to those in Example 1. TABLE 2Conductive Powder Compound A Compound B Monolithic Capacitor MagnesiumTetrabutoxy Delamination Accelerated Life naphthenate Content zirconiumContent Occurrence Test Average Sample in terms of MgO in terms of ZrO₂ZrO₂/MgO Rate Dielectric Failure Time No. (wt %) (wt %) (mol %) (n =100) Constant (hr) Evaluation 19 0.2 0.1 0.2 0 2,030 80 Good 20 0.07 0.10.5 0 3,150 76 Excellent 21 0.01 0.1 4.0 0 3,170 82 Excellent 22 0.0050.1 6.0 0 2,760 31 Good 23 2.0 1.0 0.2 0 2,140 83 Good 24 0.7 1.0 0.5 03,200 76 Excellent 25 0.1 1.0 4.0 0 3,230 75 Excellent 26 0.05 1.0 6.0 02,590 33 Good 27 8.0 5.0 0.2 0 2,020 81 Good 28 3.0 5.0 0.5 0 3,490 78Excellent 29 0.4 5.0 4.0 0 3,440 72 Excellent 30 0.3 5.0 6.0 0 3,310 39Good 31 11.0 7.0 0.2 0 1,800 28 Fair 32 5.0 7.0 0.5 0 2,690 24 Fair 330.6 7.0 4.0 0 3,120 23 Fair 34 1.0 0.0 0.0 100 — — Poor 35 5.0 0.0 0.080 2,140  2 Poor 36 10.0 0.0 0.0 53 1,730  3 Poor

[0068] As is clear from Table 2, regarding the monolithic capacitors ofSamples 20, 21, 24, 25, 28 and 29 in which tetrabutoxyzirconium as thecompound B was adhered at a content of 0.1 to 5.0% by weight in terms ofZrO₂ relative to 100% by weight of the conductive powder, and the moleratio of the amount of Zr in terms of ZrO₂ contained intetrabutoxyzirconium as the compound B, relative to the amount of Mg interms of MgO contained in magnesium naphthenate as the compound A, waswithin the range of 0.5 to 4.0, the delamination occurrence rates of allsamples were 0%, the dielectric constants were sufficiently high at3,150 to 3,490 compared to the dielectric constant of 2,140 of themonolithic capacitor of Sample 35 as the comparative example, and theaverage failure times in the accelerated life tests were very long at 72to 82 hours compared to the average failure time of 3 hours of themonolithic capacitor of Sample 36 as the comparative example, so thatthese samples were within the especially preferable range of the presentinvention.

[0069] Regarding the monolithic capacitors of Samples 19, 23 and 27, inwhich tetrabutoxyzirconium as the compound B was adhered at a content of0.1 to 5.0% by weight in terms of ZrO₂ relative to 100% by weight of theconductive powder, and the mole ratio of the amount of Zr in terms ofZrO₂ contained in tetrabutoxyzirconium as the compound B, relative tothe amount of Mg in terms of MgO contained in magnesium naphthenate asthe compound A, was less than 0.5, the dielectric constants were 2,020to 2,140 and were equivalent to or slightly inferior to the dielectricconstant of 2,140 of the monolithic capacitor of Sample 35 as thecomparative example, although these values were within the acceptablerange as a dielectric constant of a monolithic capacitor. Furthermore,the delamination occurrence rates of all samples were 0%, and theaverage failure times in the accelerated life tests were very long at 80to 83 hours compared to the average failure time of 3 hours of themonolithic capacitor of Sample 36 as the comparative example, so thatthese samples were within the preferable range of the present invention.

[0070] Regarding the monolithic capacitors of Samples 22, 26 and 30, inwhich tetrabutoxyzirconium as the compound B was adhered in the contentof 0.1 to 5.0% by weight in terms of ZrO₂ relative to 100% by weight ofthe conductive powder, and the mole ratio of the amount of Zr in termsof ZrO₂ contained in tetrabutoxyzirconium as the compound B, relative tothe amount of Mg in terms of MgO contained in magnesium naphthenate asthe compound A, exceeded 4.0, the average failure times in theaccelerated life tests were short at 31 to 39 hours and were inferior tothose of the aforementioned monolithic capacitors of Samples 20, 21, 24,25, 28 and 29 which were within the especially preferable range of thepresent invention, but the aforementioned average failure times weresufficiently long compared to the average failure time of 3 hours of themonolithic capacitor of Sample 36 as the comparative example. Inaddition, the delamination occurrence rates of all samples were 0%, andthe dielectric constants were sufficiently high at 2,590 to 3,310compared to the dielectric constant of 2,140 of the monolithic capacitorof Sample 35 as the comparative example, so that these samples werewithin the preferable range of the present invention.

[0071] Regarding the monolithic capacitors of Samples 31 to 33 in whichtetrabutoxyzirconium as the compound B was hydrolyzed and was adhered inthe content of 7.0% by weight in terms of ZrO₂ relative to 100% byweight of the conductive powder, the dielectric constants were 1,800 to3,120, and the value of Sample 31 was inferior to the dielectricconstant of 2,140 of the monolithic capacitor of Sample 35 as thecomparative example. The average failure times in the accelerated lifetests were short as 23 to 28 hours and were inferior to those of theaforementioned monolithic capacitors of Samples 20, 21, 24, 25, 28 and29 which were within the especially preferable range of the presentinvention, but the aforementioned average failure times were within theacceptable range as a dielectric constant of a monolithic capacitor, andwere very long compared to the average failure time of 3 hours of themonolithic capacitor of Sample 36 as the comparative example. Inaddition, the delamination occurrence rates of all samples were 0%, sothat these samples were within the range of the present invention.

[0072] On the other hand, regarding the monolithic capacitors of Samples34 to 36 in which the compound B was not adhered to the Ni powder, thedelamination occurrence rates were high as 53% to 100%, and the averagefailure times in the accelerated life tests could not be measured orwere very low as 3 hours or less, so that these samples were inferior.Regarding the monolithic capacitor of Sample 34, since the delaminationoccurrence rates were 100%, the dielectric constant and the averagefailure time could not be measured.

[0073] As described above, the conductive paste of the present inventionis composed of the conductive powder primarily composed of Ni, theorganic vehicle, and the compound A containing at least one of Mg and Caand being at least one selected from the group consisting of organicacid metal salt, oxide powder, metal organic complex salt and alkoxide,in which a compound B having the hydrolyzable reactive group containingat least one of Ti and Zr adheres to the surface of the aforementionedconductive powder. Therefore, for example, when the conductive paste ofthe present invention is used for forming the internal electrodes of thelaminated ceramic electronic component, the delamination does not occurduring the step of baking, and the effect of producing laminated ceramicelectronic component having superior thermal shock resistance andsuperior moisture load resistance characteristics can be exhibited.

[0074] Furthermore, the conductive paste of the present invention iscomposed of the conductive powder primarily comprising Ni and theorganic vehicle, in which the compound A and the compound B adhere tothe surface of the aforementioned conductive powder, the compound Acontains at least one of Mg and Ca and is at least one selected from thegroup consisting of organic acid metal salt, oxide powder, metal organiccomplex salt and alkoxide, and the compound B has a reactive groupcontaining at least one of Ti and Zr. Therefore, for example, when theconductive paste of the present invention is used for forming theinternal electrodes of the laminated ceramic electronic component,delamination does not occur during the step of baking, and the effect ofproducing laminated ceramic electronic component having superior thermalshock resistance and moisture load resistance characteristics can beexhibited.

[0075] In addition, since the conductive paste primarily contains Ni,the invention can contribute to reduce the cost of the laminated ceramicelectronic component, and can contribute to decrease the layer thicknessand to increase the number of layers of the ceramic layers.

What is claimed is:
 1. A conductive paste, comprising: a conductivepowder comprising Ni having a hydrolyzed compound B adhered to thesurface of the conductive powder, said hydrolyzed compound B comprisingat least one of Ti and Zr an organic vehicle; and a compound A whichcontains at least one of Mg and Ca and which is selected from the groupconsisting of organic acid metal salt, oxide powder, metal organiccomplex salt and alkoxide.
 2. A conductive paste, according to claim 1,wherein compound A is adhered to the surface of the conductive powder.3. A conductive paste according to claim 2, wherein said compound B hasan alkoxyl group.
 4. A conductive paste according to claim 1, whereinsaid compound B is an alkoxide.
 5. A conductive paste according to claim4, wherein the adhered amount of said compound B is about 0.1% to 5.0%by weight in terms of TiO₂ and ZrO₂ relative to 100% by weight of saidconductive powder.
 6. A conductive paste according to claim 5, whereinthe mole ratio of the total amount of Ti and Zr, in terms of TiO₂ andZrO₂, contained in said compound B, relative to the total amount of Mgand Ca, in terms of MgO and CaO contained in said compound A, is about0.5 to 4.0.
 7. A conductive paste according to claim 6, wherein theconductive powder has an average particle diameter of about 10 nm to 200nm and wherein compound A is an organic acid salt of Mg.
 8. A conductivepaste according to claim 3, wherein said compound B is a coupling agent.9. A conductive paste according to claim 1, wherein the adhered amountof said compound B is about 0.1% to 5.0% by weight in terms of TiO₂ andZrO₂ relative to 100% by weight of said conductive powder.
 10. Aconductive paste according to claim 1, wherein the mole ratio of thetotal amount of Ti and Zr, in terms of TiO₂ and ZrO₂, contained in saidcompound B, relative to the total amount of Mg and Ca, in terms of MgOand CaO contained in said compound A, is about 0.5 to 4.0.
 11. Aconductive paste according to claim 1, wherein said compound B is anacetylacetonate.
 12. A laminated ceramic electronic component comprisinga ceramic laminate, comprising a plurality of laminated ceramic layersand at least one internal electrode along an interface between two ofsaid ceramic layers, wherein said internal electrode is a bakedconductive paste according to claim
 7. 13. A laminated ceramicelectronic component according to claim 12, further comprising at leasttwo spaced apart terminal electrodes and having a plurality of saidinternal electrodes, each of which is electrically connected to only oneof said terminal electrodes.
 14. A laminated ceramic electroniccomponent according to claim 13, wherein said ceramic comprises adielectric ceramic barium titanate.
 15. A laminated ceramic electroniccomponent comprising a ceramic laminate, comprising a plurality oflaminated ceramic layers and at least one internal electrode along aninterface between two of said ceramic layers, wherein said internalelectrode is a baked conductive paste according to claim
 2. 16. Alaminated ceramic electronic component according to claim 15, furthercomprising at least two spaced apart terminal electrodes and having aplurality of said internal electrodes, each of which is electricallyconnected to only one of said terminal electrodes.
 17. A laminatedceramic electronic component according to claim 16, wherein said ceramiccomprises a dielectric ceramic barium titanate.
 18. A laminated ceramicelectronic component comprising a ceramic laminate, comprising aplurality of laminated ceramic layers and at least one internalelectrode along an interface between two of said ceramic layers, whereinsaid internal electrode is a baked conductive paste according toclaim
 1. 19. A laminated ceramic electronic component according to claim18, further comprising at least two spaced apart terminal electrodes andhaving a plurality of said internal electrodes, each of which iselectrically connected to only one of said terminal electrodes.
 20. Alaminated ceramic electronic component according to claim 10, whereinsaid ceramic comprises a dielectric ceramic barium titanate.